Connecting device for electric conductors.



R. R. DUNLOP. CONNECTING DEVICE FOR. ELECTRIC GONDUGTOBS.

APPLICATION FILED FEB. 23, 1910. nnnnwnn MAR. 25, 1912.

1,042,897, Patented Oct. 29, 1912.

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m MW iffy 7 UNITED STATES PATENT OFFICE.

ROBERT R. DUNLOP,v OF COLUMBUS, OHIO. ASSIGNOR TO THE JEFFREY MANUFAC- TUBING COMPANY, A CORPORATION OF OHIO.

.CONNECTING DEVICE FOR ELECTRIC CONDUCTORS.

Application filed February 23. 1910, Serial No. 545.382. Renewed March 25. 1912.

Specification of Letters Patent.

Patented Oct. 29, 1912.

Serial No. 686,129.

may readily be fired by sparks'caused byelectrical apparatus.

It is the object of this invention to provide a connecting device in which there will be no possibility of the communication to the external atmosphere of any sparks or flames that may be caused by the engagement or the disengagement of the conductor terminals and to provide in combination with such a device. a convenient, inclosed fuse box.

In the accompanying drawings I have shown one embodiment of my invention. It will be noted, however, that various changes of detail may be made without departing from the spirit of my invention.

Of the drawings, Figure 1 is a cross sectional elevation. Fig. 2 is a plan view.

Referring to the drawings, 1 represents a section of a casing which may inclose an electric motor or other electrical device. As my connecting device is especially adapted for use in gaseous mines, this casing 1 will preferably be gas and flame proof to prevent the access of gases to the interior and to prevent the communication of flame to the exterior in case of an explosion within the casing. The casing 1 is provided with a boss 2 which has a central aperture 3 provided with an annular shoulder 4. 5 is a tube or cylinder preferably of insulating material and provided at one end with an enlargement in the form of a flange or collar 6. The collar 6 is adapted to enter the aperture 3 and engage the shoulder 4. The tube 5 is held in place by means of the nut or retaining ring 7, which is adapted to fit over the tube and engage with the threads formed on the outer part of the boss 2.

8 and 9 are plugs adapted to be screwed into the ends of the tube 5. The inner ends of these plugs are provided with sockets interior of a flame proof casing.

adapted to engage the ends of a fuse 10. The type. of t'use which 1 prefer to use and which 1 have illustrated in the drawings is that in which the fuse proper is inclosed in a paper tube and connected at. its ends to brass ferrules which are secured to the ends of the paper tube. It is these brass ferrules that the sockets of the plugs 8 and 9 are adapted to engage. The plug 8 at the inner end of the tube 5 is connected to a conductor wire 11 which may lead to the apparatus inside the casing 1. The plug 9 at the outer end of the tube 5 is provided with a perpendicular split stud 12.

13 is a socket or casing, formed preferably of insulating material and adapted to fit telescopically over the tube 5 to form a closed chamber 13*. Grooves l-t are preferably formed in the outer surface of the tube 5 and these grooves are filled with a packing material which serves to make a gas and flame proof chamber between the socket l3 and the tube 5. \Vithin the socket 13 there is a plug 14 to which is connected a conductor wire 15. The plug 14: is provided with a socket 16 adapted to fit over and engage with the stud 12 on the plug 9.

A stud 17 is provided on the tube 5 and a slot 18 adapted to receive the stud 17 is formed in the socket 13. This slot 18 is provided with a part at right angles to the main part so that the socket may be locked in place on the tube by turning it through a slight angle.

It will be noted that the device which I have described,furnishes a convenient means for establishing electrical connection to the It will further be noted that the fuse 10 is entirely inclosed so that any spark or flame caused by the blowing of the fuse cannot be communicated to the external atmosphere. In case the socket 13 is removed when currentis flowing, the circuit will be broken within the flame proof chamber 13% The packing in the grooves 14 prevents explosive gases from getting into the chamber and also prevents flame from being communicated to the exterior in case there is an explosion of gases which have entered before the socket was put in place.

The external diameter of the tube 5 and the internal diameter of the socket 13 are substantially the same, except for a small working clearance and the tube with its end plug 9 is therefore especially adapled to act as a' piston to form a vacuum in'the chamber 13 as the socket is removed. The removal of the socket greatly increases the volume of the chamber 13 and the gas pressure within is correspondingly reduced. It is well known that gases are less liable to explode when under reduced pressure and advantage is taken of this fact in this device. It will also be noted that even if an explosion of the attenuated gases does take place, such an explosion would not have sufiicient force to blow the socket: away from the tube and communicate flame to the external atmosphere. When it is necessary to remove the fuse 10 to replace it, this may be done by unscrewing the plug 9. Nhen the plug has been removed the fuse is entirely free except for its frictional engagement with the plug 8. The bayonet lock formed by the stud 17 and the groove 18 serves to prevent the accidental removal of the socket.

What I claim is:

1. In a connecting device for electric conductors, the combination of a hollow flame proof cylinder, a fuse within the cylinder, terminals at the ends of the cylinder connected to the fuse, a conductor connected to each terminal, one of said conductors be ing removably connected, and means Whereby the said removably connected conductor may be connected or disconnected without the communication of sparks or flames to the external atmosphere, substantially as set forth.

2. In a connecting device for electric conductors, the combination of a hollow flame proof cylinder, a fuse within the c linder, terminals at the ends of the cylin er c011- nected to the ends of the fuse, a conductor connected to one terminal, a second conductor adapted to be removably connected to the other terminal, and a flame proof socket inclosing said removably connected conductor and adapted to fit over and telescopicallyengage the cylinder with a gas and flame proof lit, substantially as set forth.

3. In a connecting device for electric conductors, the combination of a tubular casing closed at one end, a conductor terminal in said casing near the closed end, a piston adapted to enter the open end of the casing with a gas and flame proof fit, a fuse inclosed within said piston, a conductor connected to one end of said fuse, and a terminal connected to the other end of the fuse and adapted to engage the terminal within the casing after the piston has entered the casing sufficiently to close the end thereof, substantially as set forth.

4. The combination of a flame proof machine casing having an aperture, a hollow cylinder of insulating material mounted in said aperture and entirely closing it, a fuse within said cylinder, plugs closing the ends of said 0 linder and connected to the fuse, and con uctors one within the casing and one without the casing connected to said plugs, substantially as set forth.

5. In a connecting device for electric conductors, the combination of a tubular casing open at one end, and closed at the other, a conductor terminal in said casing near the closed end, a piston adapted to enter the casing with a good working fit, and a conductor terminal connected to said piston and adapted to engage the terminal within the casing, substantially as set forth.

In testimony whereof I affix my signature, in presence of two witnesses.

ROBERT R. DUNLOP.

\Vitnesses:

E. P. SNIvnLY, DUDLEY T. F IBHER. 

